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<html>

<head>
  <meta charset="UTF-8">
  <title>无标题文档</title>
  <script type="text/javascript">
    function countDown(secs, surl) {
      //alert(surl);     
      var jumpTo = document.getElementById('jumpTo');
      jumpTo.innerHTML = secs;
      if (--secs > 0) {
        setTimeout("countDown(" + secs + ",'" + surl + "')", 1000);
      } else {
        location.href = surl;
      }
    }
  </script>
</head>

<body>
  <span id="jumpTo">5</span>秒后自动跳转到http://www.baidu.com/
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    countDown(5, 'http://www.baidu.com/');
  </script>
</body>

</html>